Journal of the Semiconductor & Display Technology (반도체디스플레이기술학회지)

The Korean Society Of Semiconductor & Display Technology (한국반도체디스플레이기술학회)
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Study on Correlation Between the Internal Pressure Distribution of Slit Nozzle and Thickness Uniformity of Slit-coated Thin Films

슬릿 노즐 내부 압력 분포와 코팅 박막 두께 균일도 간의 상관관계 연구

  • Gieun Kim (School of Electrical, Electronic & Communication Engineering, Korea University of Technology and Education) ;
  • Jeongpil Na (School of Electrical, Electronic & Communication Engineering, Korea University of Technology and Education) ;
  • Mose Jung (School of Electrical, Electronic & Communication Engineering, Korea University of Technology and Education) ;
  • Jongwoon Park (School of Electrical, Electronic & Communication Engineering, Korea University of Technology and Education)
  • 김기은 (한국기술교육대학교 전기.전자.통신공학부) ;
  • 나정필 (한국기술교육대학교 전기.전자.통신공학부) ;
  • 정모세 (한국기술교육대학교 전기.전자.통신공학부) ;
  • 박종운 (한국기술교육대학교 전기.전자.통신공학부)
  • Received : 2023.10.26
  • Accepted : 2023.12.12
  • Published : 2023.12.31
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Abstract

With an attempt to investigate the correlation between the internal pressure distribution of slit nozzle and the thickness uniformity of slot-coated thin films, we have performed computational fluid dynamics (CFD) simulations of slit nozzles and slot coating of high-viscosity (4,800 cPs) polydimethylsiloxane (PDMS) using a gantry slot-die coater. We have calculated the coefficient of variation (CV) to quantify the pressure and velocity distributions inside the slit nozzle and the thickness non-uniformity of slot-coated PDMS films. The pressure distribution inside the cavity and the velocity distribution at the outlet are analyzed by varying the shim thickness and flow rate. We have shown that the cavity pressure uniformity and film thickness uniformity are enhanced by reducing the shim thickness. It is addressed that the CV value of the cavity pressure that can ensure the thickness non-uniformity of less than 5% is equal to and less than 1%, which is achievable with the shim thickness of 150 ㎛. It is also found that as the flow rate increases, the average cavity pressure is increased with the CV value of the pressure unchanged and the maximum coating speed is increased. As the shim thickness is reduced, however, the maximum coating speed and flow rate decrease. The highly uniform PDMS films shows the tensile strain as high as 180%, which can be used as a stretchable substrate.

Keywords

Acknowledgement

This research was supported by "Regional Innovation Strategy (RIS)" through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (2021RIS-004)

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